SET serveroutput ON
DECLARE
    vx CHAR(1) ;
    CURSOR c1 IS SELECT id_student, nazwisko, imie FROM studenci ;
BEGIN
    FOR vc1 IN c1 LOOP
        BEGIN
            SELECT DISTINCT 'x' INTO vx FROM egzaminy e
                WHERE e.id_student = vc1.id_student ;
        EXCEPTION
            WHEN NO_DATA_FOUND THEN
                DBMS_OUTPUT.put_line(vc1.id_student) ;
        END;
    END LOOP ;
END ;